Herpes simplex

herpes simplex · HSV · cold sore · genital herpes · herpetic whitlow · primary herpetic gingivostomatitis

Recurrent grouped vesicles in the same place - simple in most, serious in the neonate, the immunosuppressed and the eczematous.

GPBand C

Red flags

A neonate - neonatal herpes is a time-critical emergency, and most cases occur with no maternal history, so its absence excludes nothing
Anogenital herpes in a prepubertal child - treat this as a safeguarding matter, not a sexual health referral. Discuss with paediatrics and follow the local child protection process the same day
Eczema - disseminated herpes on eczematous skin is eczema herpeticum and needs aciclovir urgently
Eye involvement - herpetic keratitis threatens sight and needs same-day ophthalmology; never give topical steroid to a red eye that might be herpetic
Immunosuppression - risk of severe, prolonged or disseminated disease
Primary genital herpes in the third trimester - urgent obstetric discussion, as it affects delivery planning
Inability to drink in a child with primary gingivostomatitis - dehydration is the reason they are admitted

Recognise

On light skin

Grouped small vesicles on a red base that ulcerate and crust, preceded by tingling, recurring at the same site.

On brown and black skin

As with zoster, the erythematous base is frequently invisible and lesions appear as discrete grey-white vesicles or shallow punched-out ulcers on unremarkable skin. The grouping, the recurrence at the identical site and the prodromal tingling are the reliable features. Healing leaves conspicuous post-inflammatory hyperpigmentation at the site, which recurs in the same place each time and can make a patient believe the lesion never cleared.

In any skin tone

Prodromal tingling or burning before visible lesions
Grouped vesicles that ulcerate, all at the same stage
Recurrence at the same site - the hallmark
Primary infection is far more severe than recurrences: widespread painful oral ulceration, fever and inability to eat or drink, especially in young children
Ask about eczema, immunosuppression, pregnancy near term, and neonatal contact

Distribution

Perioral for orolabial disease, genital or perianal for genital disease. Herpetic whitlow affects a finger. Lesions recur in the same site.

Photographs

Herpetic whitlow. Grouped vesicles on the fingers - the grouping is the diagnostic feature, and it survives any skin tone, because it is abo — Herpetic whitlow. **Grouped vesicles on the fingers** - the grouping is the diagnostic feature, and it survives any skin tone, because it is about arrangement rather than colour. The vesicle roofs look pale and slightly grey here rather than sitting on a red base.
Fitzpatrick IV-VI (Fitzpatrick type estimated from the photograph, not stated by the source) · Oladokun RE, Lehloenya RJ, Hlela C, Ubesie AC, Katibi SO, Malande OO, Eley BS · Atlas of Paediatric HIV Infection, UCT Libraries Press 2018 - Chapter 2: Viral Skin Infections, p22 · CC BY 4.0

Herpes simplex with angular stomatitis - crusted, fissured, bleeding lesions at both corners of the mouth. Worth knowing because the reflex — Herpes simplex with **angular stomatitis - crusted, fissured, bleeding lesions at both corners of the mouth.** Worth knowing because the reflex diagnosis at the angles of the mouth is angular cheilitis from candida or iron deficiency. Bilateral, painful, crusted and acute should prompt a second thought about herpes.
Fitzpatrick IV-VI (Fitzpatrick type estimated from the photograph, not stated by the source) · Oladokun RE, Lehloenya RJ, Hlela C, Ubesie AC, Katibi SO, Malande OO, Eley BS · Atlas of Paediatric HIV Infection, UCT Libraries Press 2018 - Chapter 2: Viral Skin Infections, p22 · CC BY 4.0

Provenance for every photograph in this library: image licences. How much of the corpus still has no darker-skin photograph: skin tone coverage.

Mimics

Herpes zoster (shingles), including ophthalmic and Ramsay Hunt — Zoster is dermatomal, unilateral to the midline, and usually a single episode
Hand, foot and mouth disease — Oval lesions on hands, feet and mouth rather than grouped recurrent vesicles at one site
Impetigo — Crusted perioral lesions are often assumed bacterial; herpes recurs at the same site and begins with vesicles
Syphilis - the secondary rash — A genital ulcer may be syphilitic - a painless indurated ulcer is not herpes and needs testing
Pompholyx — Herpetic whitlow gives grouped vesicles on one digit with a burning prodrome and is painful; pompholyx is symmetrical, itchy and on the palms

What to do in the ED

Oral aciclovir for significant primary infection, severe recurrence or immunosuppression; topical treatment has limited value. For anogenital disease the UK national guideline is BASHH 2024 (below), which covers first episode, recurrence, suppression and transmission; CKS is the primary-care reference. Follow local policy on the regimen
Ask about eczema in every patient with herpes, and examine eczematous skin if present
Refer genital herpes in an adult or a sexually active young person to sexual health services for testing, partner notification and counselling - an ED diagnosis is not the end of the pathway
In pregnancy near term, discuss with obstetrics the same day
For primary gingivostomatitis in a child, prioritise analgesia and assess hydration - that decides disposition
Refer any suspected ocular involvement to ophthalmology the same day
Advise on transmission, including that it can occur without visible lesions

Disposition

Treat and discharge for most presentations, with sexual health referral for genital disease. Admit neonates, the immunosuppressed with severe disease, children unable to maintain hydration, and anyone with suspected eczema herpeticum and systemic upset.

Safety-netting

Return urgently if the eye becomes painful or red or your vision changes, if the sores spread widely, if you have eczema and the rash spreads across it or becomes painful, or if a child cannot drink. Avoid contact with newborn babies and anyone with eczema or a weak immune system while lesions are present.

Sources

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